1. Field of the Invention
The present invention relates, in general, to a method of transmitting data, and more particularly, to a method in which a Digital Video Recorder (DVR) connected to a plurality of cameras can efficiently transmit image data over a network.
2. Description of the Related Art
Recently, a Digital Video Recorder (DVR) is commercialized and is thus implemented such that a plurality of monitoring cameras can be installed in a place requiring security in order to capture a monitored image, and captured image data is transmitted to a DVR, located at a remote place, and is recorded in the DVR.
FIG. 1 is a diagram showing the state in which DVRs DVR1 to DVRn are connected to each other over a network.
Each of the DVRs can be connected to, for example, 16 cameras CAM1 to CAM16. Further, unique channel numbers CH1 to CH16 can be assigned to the respective cameras.
As shown in FIG. 2, each of the DVRs includes a video display processor 10, a multi-channel Digital Signal Processor (DSP) 11, a network module 12, a controller 13, and a storage 14.
The multi-channel DSP 11 processes camera image signals respectively received through the first to sixteenth channels CH1 to CH16 as digital image data, compresses the digital image data to be suitable for a predetermined format, for example, an MPEG format, etc., and records the compressed data in the storage 14, such as a hard disc or an optical disc, for respective channels.
The controller 13 reads and reconstructs the data recorded in the storage 14 by controlling the multi-channel DSP 11 at the request of a user, thus enabling played video to be displayed on a monitor screen through the video display processor 10. Further, the controller 13 can be connected to a network, such as the Internet, through the network module 12.
Recently, when a multi-channel DVR is implemented, a request for remote playback through a network has increased. Therefore, as shown in FIG. 1, when a DVR located at a remote place (for example, DVRn) requests the transmission of image data for a specific channel, which has been recorded in the storage 14, the controller 13 controls the multi-channel DSP 11, thus reading the image data for the specific channel, for which transmission is requested, from the storage 14, and transmitting the image data through the network module 12.
Accordingly, the DVRs connected to each other over the network can share camera images recorded in respective storage blocks, with each other.
However, several problems may occur in that, when camera images for a plurality of channels are transmitted to another DVR over the network, errors occur in data transmission due to the increase in the communication load of the network. As a result, images are broken, and image display is interrupted, so that video is discontinuously played back.